Green Communications: Principles, Concepts and Practice

Chapter 10Towards Delay-Tolerant Cognitive Cellular Networks

Bi Zhao and Vasilis Friderikos

Centre for Telecommunications Research, King's College London, London, UK

10.1 Introduction

Over the last few years, we are witnessing a significant increase in the aggregate traffic in mobile networks, which is due to the proliferation of smartphones and Internet applications for mobiles. In this environment, mobile users expect to enjoy ubiquitous wireless Internet experience, which boils down to providing high-capacity connectivity to them anywhere and at any time. For sustainability reasons, operational as well as capital expenditure for mobile operators will need to be reduced. Energy consumption plays a significant role in the overall operational expenditure of a mobile operator. To this end, significant efforts have been recently placed on reducing the overall energy consumption leading to the so-called green networks.

The problem of energy-efficient transmission under delay constraints over wireless networks has been studied extensively over the past few years. Traditionally, the problem of data scheduling has been considered at the medium access control—MAC (i.e., packet) level, which considers short time intervals of the order of few milliseconds at most. Significant volume of research efforts have been placed on energy-efficient data transmission for delay-tolerant applications, especially the trade-off between transmission cost and time delay over wireless networks [1–5]. ...